Juanita ran 8.3 miles in week 1 and 12.09 miles in week 2. she used the subtraction below to determine how much farther she ran in week 2 than in week 1.

which error did juanita make?
a. she subtracted instead of added.
b. she aligned the decimal points incorrectly.
c. she did not regroup correctly when subtracting.
d. she made a computational error when subtracting.